Is God dead? It is a question that tantalizes both believers, who perhaps secretly fear that he is, and atheists, who possibly suspect that the answer is no.

Is God dead? The three words represent a summons to reflect on the meaning of existence. No longer is the question the taunting jest of skeptics for whom unbelief is the test of wisdom and for whom Nietzsche is the prophet who gave the right answer a century ago. Even within Christianity, now confidently renewing itself in spirit as well as form,...